[raticus]

I've used vinegar many times to remove mill scale, it works great, low toxic risk, safe to use... but I've always soaked the steel parts outside in a large drip pan because even the vinegar fumes can be overpowering indoors, but I just built this big 6' x 3' welding table at this job that has no welding table to work on (but lots of steel lying around, so I built one) , and the 3/16" sheet I used for the top, I'd like to do the same thing.. remove the millscale with vinegar. But this thing is a beast and I'm not gonna try to drag it outside... so I'll be soaking the top indoors.

My question is, does vinegar rust other metals in the vicinity from the fumes like hydrochloric acid does?

I share the shop with several expensive sports cars parked in it, so I want to make sure vinegar won't rust them like the fumes from hydrochloric acid would...

Thanks!

[cj737]

If the shop is that big, I struggle to believe the potency of the fumes from vinegar would cause any damage to nearby metals.

Another great product option is Toilet Bowl cleaner. Stronger than vinegar, works a bit faster, and easily neutralized by fresh water. Wet the surface, pour on the Cleaner, watch is bubble, when bubbles subside, rinse and dry and oil. Done.

[raticus]

If the shop is that big, I struggle to believe the potency of the fumes from vinegar would cause any damage to nearby metals.

The shop isn't that big, it's about 50 x 15, and I'll be leaving the vinegar soaked table just a few feet from the cars... plus, it'll be sitting in the closed shop (no windows or ventilation) for about 40 hours as I only work there every other day... I know that hydrochloric acid fumes, even for a very short time, will start to rust everything in the vicinity... and vinegar, though a much weaker acid, acetic acid, is still acid.. so there's my concern. It's probably so weak, that it shouldn't be a concern, unlike hydrochloric acid, but I'd like to make sure before possibly ruining $150k in cars.

[cj737]

There’s no way I’d leave vinegar applied to metal for 40 hours. Any acid will attack metal without stopping. You run the risk of eroding the surface and pitting it from prolonged exposure, not ambient damage caused by fumes.

[Jack Ryan]

Another great product option is Toilet Bowl cleaner. Stronger than vinegar, works a bit faster, and easily neutralized by fresh water. Wet the surface, pour on the Cleaner, watch is bubble, when bubbles subside, rinse and dry and oil. Done.

If it makes a difference to you, that probably contains hydrochloric acid.

Jack

[cj737]

Another great product option is Toilet Bowl cleaner. Stronger than vinegar, works a bit faster, and easily neutralized by fresh water. Wet the surface, pour on the Cleaner, watch is bubble, when bubbles subside, rinse and dry and oil. Done.

If it makes a difference to you, that probably contains hydrochloric acid.

Jack

To clarify, here’s the SDS. https://alpineclean.com/wp-content/uplo ... leaner.pdf

[Jack Ryan]

Another great product option is Toilet Bowl cleaner. Stronger than vinegar, works a bit faster, and easily neutralized by fresh water. Wet the surface, pour on the Cleaner, watch is bubble, when bubbles subside, rinse and dry and oil. Done.

If it makes a difference to you, that probably contains hydrochloric acid.

Jack

To clarify, here’s the SDS. https://alpineclean.com/wp-content/uplo ... leaner.pdf

Ah, sorry - I didn't realise "toilet bowl cleaner" was a product. I thought you meant those cleaners in general which do very often contain hydrochloric acid.

I see the product "toilet bowl cleaner" only contains citric and lactic acids.

Learnt something new - thanks.

Jack

[raticus]

Update on my vinegar action... So while I was working, i used a 6 foot long 13 inch wide sheet of the same steel as a test piece to see how much fumes it would create in the 8 hours that I worked that day. I set up the sheet on a couple of cinderblocks in the middle of the shop, taped up the edges tightly with painters tape (had very little duct tape available) to create a dam effect as I didn't have a pan big enough (I usually use the big automotive oil drip pans to soak sheet in vinegar but they don't make anything this big)... I poured in about a 1/4" high of vinegar (typical 5% strength), and surprisingly, it only had a couple of small drip leaks, mostly on the corners... I flap disced up a piece of square 2x2 tubing nice and shiny, and placed it on the floor about a foot away from it... to use as my 'coal mine canary' to see if it would start rusting up... At the end of the day, the vinegar was doing its job, albeit slowly as expected, but there were no telltale signs of the fumes rusting my 'canary'.

So at the end of the day, I taped up the 6 foot x 3 foot table top (the same 3/16" hot rolled sheet), used the small amount of duct tape I had and taped up the corners with that, and used painters tape on the rest... Gave instructions to my boss on when to clean it off and wash the table top using baking soda the next day (as I wasn't working the following day), when it looked ready... when the vinegar dissolved most of the millscale. This ended up being around 20 hours later... and it came out excellent. My boss used a floor jack to tip the table slightly (the beast is not a real thick welding table, but it's not light at all.. I can barely lift one side a few inches up... the tubing I used was 1/4" wall), so he could drain all the used vinegar onto one corner. The next morning I came in to find a perfect cleaned, gray table top, and after a few minutes with a flap disk to lightly clean it up to shiny metal... it came out great. And there were no fume issues to any of the steel in the shop right next to it (including the all tube, car chassis I'm building)...

So if anyone wants to know... vinegar does not make enough fumes, even in a large gallon amount in almost a full 24 hour period, to effect any other steel in the vicinity.

Total cost to remove millscale... around $2 for the vinegar, $2 in baking soda, and about $5 in tape... under $10, and environmentally friendly.